Its a bit hard to measure with all the twists and turns but I followed it as well as I could and on my large frame I got about 29" front and 50" rear. Measured a few times and was +/- 2". My front cable is a bit longer than I would like, probably by 4 - 6". Maybe you could email Ibis to get their recommended lengths.

Mine's 33 and 50. Large frame. 510mm a2c fork (same as OEM). 1 inch spacer under stem. The dealer (Over the Edge Sports, Fuita, CO) set it up for left hand front brake. I changed it over to right hand front. Length is good for both sides.

Brake Hose Length

Howdy All,
We spec an 85 cm tube for the front brake and 140 cm for the rear. Depending on the fork you use, the front may be long.
We currently stock one tube length for front and one for rear. Bear in mind we need to accommodate folks buying 160 mm travel forks too.
Also, as pointed out by derby, some people use different spacers under their stems, throwing in yet another variable.
I'd recommend having a bleed kit and the ability to shorten the hydraulic tubing, or having your lbs do it. Shimano and Hayes have the parts availble to do this, as do many distributors.

Shimano has a technical document here outlining the various bits needed for their cutable hose.